"Castle" is a song by American singer and songwriter Halsey. Originally recorded for her debut studio album, Badlands (2015), it was re-recorded for the soundtrack to the 2016 film The Huntsman: Winter's War. It was released on April 9, 2016 through Capitol Records as a promotional single from the record. "Castle" was co-written by Halsey and the track's producer, Lido. The song was used in commercials and in the teaser trailer to promote the film. The song has background vocals of a choir singing Agnus Dei. She is singing about taking the throne and the kingdom is locked up which is a reference to her album Badlands.